1. Field of the Invention:
The present invention relates to an information reproducing system, and more particularly to an information reproducing system which can play back successively a plurality of recording mediums such as CDs (Compact Disks), LVDs (Laser Vision Disks), or the like.
2. Prior Art:
There are known CD players for reproducing information which is recorded on CDs. A CD player operates to optically read information recorded on a CD which is rotating thereby to reproduce the information under the control of a playback control unit. Before the playback operation is started by such an information reproducing system, TOC (Table of Contents) information, which is recorded as control data on a CD together with information to be reproduced, is read from the CD into a RAM in the playback control unit. The playback operation is controlled on the basis of the TOC information which is thus read. The TOC information contains various inherent data relative to the information recorded on the CD, such as the number of music pieces recorded on the CD, and the periods of time of the music pieces, for example.
Heretofore, TOC information is read from a CD into the playback control unit each time such a CD is loaded in the CD player. When the playback of a CD is completed and a next CD is loaded in the CD player, the TOC information from the CD that has been played back is no longer held by the playback control unit, and TOC information is newly read from the next CD into the playback control unit.
Recently, there has been developed a multidisk CD player in which a plurality of CDs are stored in a single magazine (a group of recording mediums) and such a magazine is loaded and played back, so that the plural CDs can be handled for easy playback. The multidisk CD player has an automatic CD changer which automatically selects and plays back desired CDs successively.
One conventional multidisk CD player will be described below.
A multidisk CD player employs a magazine which stores a plurality of CDs. The multidisk CD player has an automatic CD changer for automatically selects a desired CD, a drive unit for rotating selected CD, a pickup for optically reading information recorded on the CD, a signal processor for converting the read information into a analog signal, a display/operation panel for displaying a playback condition and operating the CD player for playback, and a playback control unit (playback control means) for controlling the entire playback operation of the CD player. Such a multidisk CD player is also to read TOC information from each of the CDs which are stored in the magazine.
The multidisk CD player can play back a plurality of CDs successively, and can operate according to programmed information which represents the sequence according to which stored CDs are to be played back, the sequence according to which recorded music pieces are to be played back, and other playback modes. Such programmed information is manually established by the user of the CD player when the magazine is loaded. The programmed information is written in a RAM in the playback control unit when the magazine is loaded into the CD player. The programmed information is treated in the same manner as the TOC information. More specifically, programmed information is established with respect to each magazine. When a magazine is replaced with another magazine, the programmed information which has been established with respect to the previous magazine and read into the playback control unit is erased, and programmed information with respect to the newly loaded magazine has to be established and read again even if such programmed information is the same as the programmed information regarding the previous magazine.
One problem of the conventional multidisk CD player is therefore that programmed information which has been established and read with respect to a magazine is erased each time the magazine is replaced with another magazine. This requires the user to establish programmed information each time a new magazine is loaded into the CD player, but such a procedure is complex to perform. Any programmed information which has been read into the playback control unit is also erased when the power supply of the CD player is turned off, and hence has to be established again when the power supply is turned on again. If programmed information which has been established with respect to a certain magazine is stored and used again, then the user is not required to follow the above complex procedure.
However, since the storage capacity available for the storage of programmed information is limited, when the storage capacity becomes full, the stored information of lower priority has to be erased so that new programmed information can be stored.
On the other hand, if any stored information should automatically be erased, some important information might be lost.